Scaling Supercapacitive Swing Adsorption of CO2 Using Bipolar Electrode Stacks

Abstract

Supercapacitive Swing Adsorption (SSA) modules with bipolar stacks having 2, 4, 8 and 12 electrode pairs made from BPL 4x6 activated carbon were constructed and tested for carbon dioxide capture applications. Tests were performed with simulated flue gas (15%CO2 /85%N2) at 2, 4, 8 and 12 V, respectively. Reversible adsorption with sorption capacities (~58 mmol·kg-1) and adsorption rates (~38 µmol·kg-1·s-1) were measured for all stacks. The productivity scales with the number cells in the module, and increases from 70 to 390 mmol.h-1m-2. Energy efficiency and the energy consumption improved with increasing number of electrodes from 67% to 84%, and 142 to 60 kJ·mol-1, respectively. Overall, the results show that SSA modules with bipolar electrodes can be scaled without reducing the adsorptive performance, and with improvement of energetic performance.

Supercapacitive Swing Adsorption of Carbon Dioxide: Current Status and Perspectives

“…Recently, they scaled SSA modules by connecting bipolar electrode pairs in series for 2, 4, 8, 12 pairs stacks, applying corresponding final voltages (2 V, 4 V, 8 V and 12 V) and flow rates (6 sccm, 16 sccm, 24 sccm and 36 sccm) to them, respectively. [73] It is noticed that the absolute adsorption capacity and productivity of CO 2 in the module increase proportionally with the increase in the number of electrode pairs, i. e., from 151 to 787 μmol, and from 70 to 390 mmol h À 1 m À 2 , respectively, and that the increase in electrode pairs reduces energy consumption, i. e., from 202 to 60 kJ mol À 1 . The scalability was demonstrated across all stacks, with the adsorption capacity (~58 mmol kg À 1 ) and adsorption rate (~38 μmol kg À 1 s À 1 ) remained unchanged across all stacks.…”

Oxygen-assisted supercapacitive swing adsorption of carbon dioxide

“…Since the first report on SSA by our group, significant technological progress has been made towards improving the cell design, increasing the CO2 adsorption capacity, and demonstrating the scalability potential through bipolar electrode stacks. [16][17][18] Fundamental studies on SSA focused on the collection of energetics and adsorptive performance metrics as a function of charging protocols, electrolyte composition, and concentration. [19][20][21] Recent studies from us and other researchers highlighted the possibility of enhancing the CO2 sorption capacity by tuning the voltage window, investigated critical factors contributing towards performance improvements, and proposed biomass-and non-biomass derived carbon-based materials with high surface areas and capacitances for enhancing SSA performance.…”